New research suggests that napping and a good night's sleep help the brain consolidate learning.
Sleep is a bit of a mystery - no-one is quite sure why it's essential to health and wellbeing. But if you suffer from sleeping difficulties, you'll be aware that tiredness has a real effect on your mental performance. Researchers at Harvard University now shed new light on the role of sleep in learning and information processing.

They had a group of volunteers perform a simple visual task and found that their performance deteriorated as the day went on. They ascribed this not to generalised fatigue but to overload of the brain circuit involved in the task. But taking a nap during the day seemed to refresh the brain and performance did not tail off. Other experiments suggested that a late stage of night sleep - which early risers may miss out on - seemed to help the brain consolidate the 'overload' of the previous day. So if you feel like a daytime nap - go ahead, as it could keep you mentally sharp. And see if you can get a full eight hours during the night.